Distance–time graphsCan you put these items in order

of their top speeds?

April 19, 2023

Formula 1 car

Jet fighter

Human

Laser beam

Snail

Cheetah

Tortoise

Distance–time graphs

Can you put these items in order of their top speeds?

April 19, 2023

Snail 2 mm/s

Tortoise 5 cm/s

Human 12 m/s

Cheetah 34 m/s

Formula 1 car 100 m/s

Jet fighter 700 m/s

Laser beam 300 000 000 m/s

Distance–time graphs• How can a d-t graph show:

– something is stationary?– Moving at a constant speed

• How can we calculate average speed?

April 19, 2023

The Eurostar train runs on the UK’s only high speed rail line. It can reach a maximum speed of 186mph. London to Paris takes 2 hours 15 mins a distance of 211miles.

Looking at graphs

• Which graph shows a stationary object?• Which graph shows an object moving at

constant speed?

Distance

(metres)

Time (sec)

Distance

(metres)

Time (sec)

Looking at graphs

Distance

(metres)

Time (sec)

Distance

(metres)

Time (sec)

• Stationary – no change in distance

• Constant speed – same change in distance every second.

Describe this journey in as much detail as you can.

• What was the speed at A, B and C?• What was the average speed?

Time (sec)

Distance

(metres)

0 10 20 30 40 50 60

100

50

0

A

B

C

Speed = distance

time

Measuring speed

Speed = distance ÷ time

Trolley

No. of books

Distance (m)

Time (s) Speed (m/s)

1

2

3

4

5

Books

ramp

Diagram

1. Set up the equipment as shown.

2. Measure and mark a distance down the ramp.

3. Measure the time to roll down the slope.

Summary

• The steeper the line on a distance time graph the greater the speed.

• Speed = distance travelled (m) (m/s) time (s)